Wellbores are sometimes drilled into subterranean formations containing hydrocarbons to allow recovery of the hydrocarbons. In some situations, the wellbore is drilled in a seabed from a vessel at the sea surface. The wellbore is also produced through the fluid connection between the subsea wellhead and the surface vessel. A production tubing may be used in the subsea well for purposes of communicating produced well fluids from subterranean formations of the well to equipment at the sea floor. The top end of the production tubing may be threaded into a tubing hanger that, in turn, is seated in a well tree for purposes of suspending the production tubing inside the well.
For purposes of completing a subsea well and installing the production tubing, the production tubing typically is lowered into a marine riser string that extends from a surface platform, such as the surface vessel, down to the subsea equipment (a well tree, blowout preventer (BOP), etc.) that defines the sea floor entry point of the well. The marine riser string forms protection for the production tubing and other equipment (described below) that is lowered into the subsea well from the platform. At the sea surface, the top end of the production tubing is coupled to (threaded to, for example) a tubing hanger that follows the production tubing down through the marine riser string. A tubing hanger running tool is coupled between the tubing hanger and a landing string, and the landing string is lowered down the marine riser string to position the tubing hanger running tool, tubing hanger and production tubing in the well so that the tubing hanger lands in, or becomes seated in, the subsea well head.
The production tubing can now be used to communicate produced hydrocarbons from the well to the surface platform, or to communicate injection fluids from the surface platform to the well in cases of well intervention or other remedial operations. During these operations, the strings and tubing between the surface platform and the well can experience forces and stresses. For example, the surface platform may experience lateral rig heave or another unknown impact that shifts the surface platform relative to the wellhead. Surface platform positioning devices may work improperly and cause the surface platform to move laterally relative to the wellhead. Other such events that compromise the position of the surface platform over the wellhead can also create stresses in the strings and tubing coupled between the surface platform and the wellhead.